Reversible power transmission



Dec.' I, 1942.

w. P. SCHMITTER REVERSIBLE POWER TRANSMISSION ATTORNEY.

Patented Dec. 1, 13942 REVERSIBLE POWER TRANSNUSSION Waiter P. Schmitter, Wauwatosa, Wis., assignor to The Falk Corporation, Milwaukee, Wis., a corporation of Wisconsin Application October 30, 1939, Serial No. 301,930

(Cl. 'M -379) Claims.

This .invention relates to reversible power transmissions.

An object of the present invention is to provide, in a power transmission system, an improved reversing mechanism of simple compact form, readily operable to quickly reverse the direction of operation.

Other more specific objects and advantages will appear from the following description of an illustrative embodiment of the invention.

In the accompanying drawings:

Figure l is a vertical sectional view of a speed reduction gear set .equipped with a reversing mechanism constructed in accordance with the present invention.

Fig. 2 is a fragmentary horizontal sectional view.

Fig. 3 is a sectional view on a larger scale of the air admission device shown in Fig. 1.

The speed reduction gear set selected for illustration is designed for marine use. It comprises a conventional gear I8 meshing -with a pinion II, both arranged within an appropriate housing I2. The gear IIl is shown carried by an integral shaft I3 suitably journalled in housing frame members I4 and I5. The shaft I3 extends rearwardly fromthe housing for'connection with a propeller shaft (not shown) .Pfand is provided at its forward end with a thrust bearing IB adapted to sustain the propeller thrust. The pinion II is shown carried by an integral shaft I1 journalled at its rear end in a thrust bearing I9 in frame member I5 and projecting through and forwardly beyond a be'aring I8 in the frame member I4. To facilitate assembly, the housing and frame members I4 and I5 are horizontally split in planes passing through the axes of shafts I3 and I1.

In this instance the pionion shaft I1 is driven in either direction from a unidirectional driver, such as the flywheel of an internal combustion '\engine, through two selectively operable clutches. The driver, pinion shaft, and clutches are preferably coaxially disposed for the sake of compactness. The clutches shown are of the uid pressure type, such as described in the Fawick Patent No. 2,141,645, affording torsional and angular flexibility to damp out`torsional cs -V cillations and to compensate for inaccurate alignment, and also affording an ease of control not ordinarily available inv clutches of 'mechanical type.

Each of the clutches shown includes an exible annular fluid pressure container 2I-22, of

lli

rubber or rubber and fabric, carried by the ywheel 20. In this instance each container 2I-22 is attached to a ring 23-24, fixed to the ywheel, and is expandable into frictional gripping engagement with the periphery of an inner concentric rotor or wheel 25-26.

The wheel 25 is keyed or otherwise xed to the rearwardly projecting end of the pinion shaft I1, and the wheel 26 is supported by the shaft I1 through appropriate bearings 21 whichpermit free rotation thereof relative to the shaft. The wheel 25 is thus permanently connected to the pinion I I for rotation therewith, the other wheel 26v being connected to the pinion for reverse rotation through gearing such as will now be described.

Gearing for this purpose may assume various forms, but that shown comprises a bevel gear 28 fixed to the hub 29 of the wheel 26 and meshing with two coaxial bevel gears 38 which in turn mesh with a bevel gear 3I keyed or otherwise xed to the pinion shaft I1, preferably between the pinion II and its bearing I8. The two bevel* gears 3l) are preferably fioatably mounted in such manner as to insure that the total torque load transmitted by them fromgear 28 to gear 3l is equally divided between them, and so that the tangential reactions of the two gears 30 upon the gear 28 are equal and in opposite directions, thereby avoiding a radial thrust upon the projecting end of the pinion shaft I1 that might otherwise be imposed by an unbalanced tan-- gential reaction resulting from the torque load.

In this instance each gear 30 is' keyed or otherwise fixed to a separate hollow shaft 32 (Fig. 2) journalled at its outer end in appropriate thrust sustaining bearings 33 xed in a cage 34. Each cage 34 is closely fitted for free axial movement within a horizontal bore 35 formed in the housing frame member I4. .A roller bearing 36 supports the inner end of each hollow shaft 32, the outer race of the.' bearing 36 being fixed in the frame member I4 while the inner race is fixed'to the shaft 32 but freely movable axially with respect to the bearing rollers. 32 are thus mounted for free axial movement radially ofthe gears 28 and 3| and are thus yieldable to radial thrusts imposed by the latter as a result of gear tooth reactions therebetween.

However, provision is made for constraining the two gears 30 to move axially as a unit. For this purpose a tie rod 31 is provided extending through each of the hollow shafts 32, the inner ends of the rods being fixed to a free-floating ring segment 33 underlying the pinions'haft I1,

Both gears 30 and their supporting shafts transmits its one half share of the total torque load.

The arrangement is such that when the container 2| of one of the clutches is expanded into pressure contact with wheel 25, the pressure in V the other container 22 being released, the pinion Il is driven in one direction by and with the flywheel 20; and when the pressure in container 2| is released and the container 22 of the other clutch expanded into pressure contact with the wheel 26, the pinion *Il is driven in the opposite direction through the gears 28, 30, and 3|. The containers 2l and 22 are expanded and released by the application and release of uid pressure, preferably air pressure, transmitted in this instance through the pinion shaft I1.

For this purpose a pair of concentric tubes 39 and 48 are provided which extend axially through the pinion shaft I1 and are freely rotatable relative thereto. Both -tubes are connected to rotate with the fly-wheel 28, the outer tube 39 being connected thereto through a pipe 4| which communicates with the interior of a head 42 fixed on the rear end of the tube 39, and the inner tube 40 being connected to the ily-wheel through va similar pipe 43 which communicates with the interior of a head 44 xed to the projecting end of the irmer tube. Pipe 4| communicates with the container 22 of one clutch through appropriate passages 4'5, yand pipe 43 communicates With the container 2| of the other clutch through appropriate passages 46. A head 41, fixed to the forward ends of both tubes 39 and 40, has a central passage 48 (Fig. 3) which communicates with tube 40 and a plurality of passages 49 which communicate with the tube 39.

Provision is made for admitting and releasing `fluid pressure to or from the tube 39 through the passages 49 or to or from the tub'e 40 through the passage 48 while the head 41 and tubes are rotating. The device shown for this purpose comprises a ilanged housing 50 fixed to the head 41 ister with the passages 49 and provide communication between them and the interior of hosing 50. 'I'he plate 54 is provided With a central boss 56 having a central passage 51 which provides communication between the passage 48 and a tube 58 carried by the boss and extending axially through the trunion into the non-rotating housing 53. The tube 58 is additionally supported and fixed by a nut 59 seated in the housing 50 and perforated to afford communication between the housing 50 and trunion 5I.

The non-rotating housing 53 has a chamber 60 which communicates with the tube 58 and with a pipe 6|. The chamber is sealed by a flexible diaphragm in the form of a, thin metallic disk 62 supported at its periphery within the non-rotating housing 53 and having a central opening 63 which registers with the bore of the tube 58. A thickened annular portion 64 surrounding the opening 63 is in sealing contact with the end face of a nipple 65, fixed to the end of the tube 58.

A second chamber 66 within the non-rotating housing 53 communicates with a pipe 61 and with the rotating housing 50 through the hollow trunion 5|. Opposite sides of the compartment are sealed by flexible diaphragms 68 and 69 somewhat similar to diaphragm 62, both being supported at their peripheries within the housing 53. Diaphragm 68 has a central opening 10 which registers with the bore in the trunion 5| and which is surrounded by a thickened portion 1| which is in sealing contact with the end face of the trunion; and diaphragm 69 has a central opening 12 to accommodate the tube 58 and which is surrounded by a thickened portion 13 which is in sealing contact with a flange 14 on the nipple 65.

The arrangement is such that whenever fluid pressure is supplied to the pipe 6|, from any appropriate pressure source, it is transmitted therefrom through the chamber 60, tube 58, passages 51 and 48, tube 40, pipe 43, and passages 46 to the pressure container 2| of one clutch to close that clutch and thus effect forward operation of the pinion Il and gear l0. To reverse the operation, the pressure in pipe 8| is released and fluid pressure applied to the other pipe 61, this pressure being transmitted through chamber 66, trunion 5|, housing 58, passages 49, tube 39, pipe 4|, and passages 45 to the pressure container 22 of the other clutch to thereby close the latter and cause the pinion Il and gear I0 to be reversely driven through the gears 28, 30 and 3|. It will of course be understood that fluid pressure admitted to the chamber 60 acts on the diaphragm' 62 to increase the sealing pressure thereof against the nipple 65, and that similarly fluid pressure admitted to chamber 66 increases the sealing pressure of the diaphragm 68 against the trunnion 5| and the sealing pressure of daphragm 69 against the flange 14 on the nipple 65.

Various changes may be made in the embodiment of the invention hereinabove specifically described without departing from or sacrificing the advantages of the invention as defined in the appended claims.

I claim:

1. A reversible power transmission comprising a rotary driver, a pair of clutches disposed coaxially thereof and arranged to be driven thereby, a shaft connected with one 'of said clutches, a gear rotatably mounted on and supported by said shaft and connected with the other of said clutches, a second gear operatively connected to and supported by said shaft, and torque transmitting means connecting said first and second named gears for rotation in opposite directions', said last named means including a plurality of torque transmitting elements symmetrically disposed with respect to said shaft and freely movable as a unit transversely of said shaft so as to automatically distribute the torque load on said elements and thereby effect such rotation Without imposing a radial'load on said'shaft.

2. A reversible power transmission comprising i a rotary driver, a pair of clutches arranged to beA named gears to thereby automatically equalize the load on said plurality of gears.

3.- In a power transmission the combination rotatable with said driver for conducting uid' pressure to said glands selectively.

4. In a power transmission the combination of a housing, a gear train including a gear therein, a separately mounted driver outside of said housing at one side thereof, two clutch elements supported by said housing and coaxially disposedwithin said driver, a driving connection between each of said clutch elements and said gear train, two fluid pressure glands within said driver and radially -expansible to effect a driving engagei ment between said driver and said clutch elements alternatively, said glands being flexible to accommodate misalignment between the axes of said driver and said clutch elements, and means extending axially through said gear for supplying iiuid pressure to said glands selectively.

5.- In a power transmission the combination of a housing, a pinion therein,` a shaft supporting said pinion and projecting from said housing, a, bearing inv said housing providing support for the projecting end. of said shaft, a bevel gear fixed to said shaft at one side of said bearing, a second bevel gear supported by and surrounding said shaft at the opposite side of said bearing, means including a third bevel gear providing a driving connection between said rst named gears, a rotary driver, and two clutches alternatively operf able to connect said driver to said shaft or to said second named gear.

WALTER P. SCHMITTER. 

